Crude Oil Separator Foam Problems

Separator design and sizing is often done without full appreciation or understanding of the problem of foam. Many field and lab tests using probes and windows have shown that foam is often the major problem for the typical crude oil degassing, flash, separator. Often more than 50% of a separator's volume is occupied by foam. All crude oils should be considered foamy because any oil can create large foam volumes under certain conditions. The size of the separator foam volume depends on many interrelated factors. There is no single magic key to determining foam volume. Derating of the allowable gas velocity to account for foam is a grossly inaccurate method of separator sizing. The K-factor in the allowable gas velocity equation correlates to none of the factors that affect foam volume. Fritted bubbler and pressure bomb indexers are a step in the right direction but are still inadequate. We have developed a pilot operation which with proper foam generation can produce meaningful oil foaminess measurements. To predict separator foam volumes, several adjusting factors must be applied. The heart of an accurate foam volume prediction is an abundance of field experience correlated with laboratory pilot data, which includes all pertinent variables.